Indicates if the specified Serial port is ready. On the Leonardo, Serial indicates wether or not the USB CDC serial connection is open. For all other serial instances, this returns true.

This was first introduced in Arduino 1.0.1.

Changed lines 28-29 from:

boolean : returns true if the specified serial port is available. On the Leonardo Serial indicates wether or not the USB CDC serial connection is open. For all other serial instances, this returns true.